32 



TREPHININa S( PERIOR MAXILLIARY SINUSES. 



insure the permaneucy of the opening through the turbi- 

 nated bone. In case of severe hemorrhage the nasal and 

 sinusal cavities may be tamponed for twenty-four hours with 

 a long strip of gauze which may be secured if necessary by 

 suturing to the lips of the trephine wound. In practice the 

 operation can be best carried out generally with the animal 

 in the standing position the operative area being first 

 anaesthetized by the use of cocaine or by inducing artificial 

 oedema. In the standing position we largely avoid the 

 danger of aspiration of fluids and the hemorrhage is greatly 

 lessened. 



4. TREPHINING THE SUPERIOR MAXILLARY SINUSES. 

 Plates IIl-X. 



Uses. Empyema, diseased teeth, odontomes or other 

 tumors. 



Instruments. Same as for the frontal sinuses. 



x\natoniically there are two maxillarj^ sinuses, superior, 

 SM, and inferior, IM, Plates III-X, having a thin im- 

 perforate bony partition between them. This partition 

 shifts somewhat in position with age and in case of disease 

 undergoes profound changes in location and is frequently 

 totally obliterated in cases of empyema, dental cysts and 

 other affections. If the sinusal partition be present, good 

 drainage of the superior sinus may demand the surgical 

 destruction of the partition so that some authors advise 

 trephining directly upon the partition in ordei to open the 

 two cavities simultaneously. 



In extensive disease of either sinus the partition between 

 the two frequently becomes obliterated so that there remains 

 but one sinus to open ; in limited disease the opening of both 

 cavities is ill advised. In extensive disease the existence 

 of a partition may generally be ignored in operating and 



